Packaging

ABSTRACT

A method of packaging live seafood including the steps of providing a sealable container, wherein the container includes a plastic tray having an interior volume and an upper peripheral edge, placing the live seafood in the container, and replacing the atmospheric gas in the container with a gas mixture including only CO2 and O2, with an O2 content of at least 50% by volume, and a CO2 content of at least 20% by volume, and sealing the container with a layer of flexible film including a sheet of flexible sealable film sealed to the upper edge of the tray, the flexible film having an Oxygen Transmission Rate (OTR) of at least 1500.

BACKGROUND

The present invention relates to the field of live seafood packaging. In particular, the present invention provides an improved live seafood packaging method, and package, that improves mortality rate of packaged live seafood, as compared with known live seafood packaging.

In the marketing of seafood, such as mussels and other shellfish, crustaceans and so on, it is essential to deliver a live product, to permit a restaurant or seafood market to offer the best possible seafood to the consuming public. Bringing live seafood to inland markets can be problematic, and expensive. The most obvious, and expensive, way to do so is to expedite transport of the live animals by air, preferably in an aqueous environment simulating their natural environment. This is effective, but expensive, because of the weight involved.

There have been several packaging methods proposed to keep live seafood alive during transit. In JP58129930, the product is packaged in a mixture of O₂ and CO₂, after it has been injected with alkaline solution of pH 7-12. This method, then, requires additional handling of each item, and the use of an additive thereto, and is therefore not economically feasible.

In U.S. Pat. No. 6,238,716, a packaging method using 50%-90% of a CO₂ and O₂ mix including 25%-50% O₂ is proposed. It has been found to be effective on some shellfish, but is ineffective in relatively long time frame shipping and storage.

Applicants previous patent CA 2489738 dated 2007-02-02 discloses a method for packaging live seafood, using a modified atmosphere gas mixture of CO₂ and O₂ in a package sealed with a multi-layer high barrier film. The gas mixture is preferably about 80% O₂.

While the Applicant's previous packaging method has proven quite effective, the multi-layer films used are expensive, as is the 80% O₂ gas mixture.

The object of the present invention, therefore, is to provide a package for live seafood, utilizing a lower O₂ gas mix, with an O₂ permeable film.

After extensive experimentation, the Applicant has determined that an improved mussel and other seafood species mortality rate is obtainable using a package filled with a modified atmosphere gas mixture comprising only O₂ and CO₂. The package comprises a formed leak-proof plastic tray, sealed with a food-compatible film having an Oxygen transmission rate (OTR) of at least 1500 OTR. The OTR of the film may be higher, up to 10K or higher, as long as the film is leak-proof.

OTR is measured in cm³ of O₂ per m² per day/bar. It has been found that at levels in excess of about 15000 OTR that the packaging ceases to be leak-proof. Since live mussels need to be kept moist, as well as oxygenated, use of high OTR film that permits water to be lost is not within the scope of the present invention.

SUMMARY

The present invention provides:

1. A method of packaging live seafood comprising the steps of providing a sealable container,

-   -   wherein said container comprises a plastic tray having an         interior volume and an upper     -   peripheral edge, placing said live seafood in said container,         and replacing the atmospheric     -   gas in said container with a gas mixture comprising only CO₂ and         O₂, with an O₂ content of     -   at least 50% by volume, and a CO₂ content of at least 20% by         volume, and sealing said container with a layer of flexible film         comprising a sheet of flexible sealable film sealed to     -   the upper edge of said tray, said flexible film having an Oxygen         Transmission Rate (OTR) of at least 1500.

2. A method as in (1), wherein the OTR of said film is from 1500 to 15000.

3. A method as in (2), wherein the OTR of said film is about 10000.

4. A method as in (2), wherein said live seafood is mussels.

5. A method as in (2), wherein said live seafood is lobster.

6. A package for use with live seafood comprising a tray with a flat floor and side walls extending upwardly from the floor, the side walls being of a sufficient height to accommodate a predetermined number of live organisms, said side walls being contiguous with one another and said floor to define a leak proof open tray, and the upper edges of said side walls formed flat lip extending around the peripheral edge of said tray; and a layer of flexible sealable film sealed to the upper edge of said tray to enclose a modified atmosphere comprising at least 20% CO₂ and at least 50% O₂, said flexible film having an Oxygen Transmission Rate (OTR) of at least 1500 cm³O2/m²/day bar.

7. A package as in (6), wherein the tray is substantially rectangular, and the corners of said rectangular tray are rounded.

8. A package as in (7), wherein said tray is molded from plastic.

9. A package as in (7), wherein said film, has an OTR in the range of 1500 to 15000 cm³ O₂/m²/day bar.

10. A package as in (7), wherein the OTR of said flexible film is about 10,000 cm³ O₂/m²/day bar to above 250,000 cm³ O₂/m²/day bar.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings that illustrate the present invention by way of example:

FIG. 1 is a perspective view of a tray for a package for mussels, lobsters or the like according to the present invention.

FIG. 2 is a front view of the package shown in FIG. 1, with film applied thereto.

FIG. 3 is a cross-sectional view through line III-III in FIG. 2.

DETAILED DESCRIPTION

As shown in the drawings, the present invention relates to a package, and also to a method for packaging live mussels, lobsters and the like. The package comprises a tray 2 made of suitable food-grade leak proof plastic material. The selection of a leak proof plastic material will be a matter of choice for one skilled in the art.

The tray 2 is molded from a single piece of plastic so as to be entirely leak proof. The corners 8 are rounded, to eliminate or reduce the chance of cracking the plastic. Similarly, the transition edge 9 between the end panels 3 and the floor panel 6 of the tray 2, as well as the transition edge 9 between the side panels 4 and the floor panel 6 are also rounded, to prevent or minimize cracks in the tray 2, which would cause the package to leak.

The tray 2 is generally rectangular in a preferred embodiment. This permits the most efficient packaging of multiple trays, and also facilitates use of machines to assist in packaging. Moreover, as will be explained herein, the tray 2 is sealed with a flexible film 5, so use of rectangular trays minimizes film usage and waste. Other shapes, such as circular or hexagonal, may be used for tray 2, if desired.

A flat lip 7 is formed around the upper perimeter of the tray 2, and is continuous along each side panel 3, font and back panels 4, and corners 8. The function of lip 7 is to provide continuous flat surface for the application of film 5 to cover tray 2.

As the product is placed in the tray 2, and before the film 5 is applied to the open top of the tray the gas in the tray, primarily ordinary air is purged, and a gas mixture only of O₂ and CO₂ with at least 50% O₂ and at least 20% CO₂, together with small amount of water, is blown into the tray 2, which is then sealed with film 5.

It will be noted, as regards high OTR film, that highly permeable film of about 10,000 OTR has been used to package fresh fish in vacuum packs. It is used in this type of fish packaging by Plastopil for its ability to adhere to the fish fillets, thereby to present the product well, and the fact that its very high permeability promotes the growth of anaerobic bacteria. This use is different from the Applicant's, in that use for fish packaging is not designed to keep the fish alive. Moreover, one would typically not expect that packaging for fresh fish, which stays fresher in low O₂ environment to be appropriate for live seafood organisms. However, when used for fresh fish, there is in fact no atmosphere inside the film, as the film is vacuum sealed around the fish piece.

The film of the package of the present invention is applied in a similar manner to that of CA 2489738, around the rim of a formed plastic foam tray in which the mussels have been deposited, with a quantity of water and in a modified atmosphere of O₂ and CO₂ containing at least 50% O₂ and 20% CO₂.

A film of at least 1500 OTR is sealed around the edge of the tray. The film should be leak-proof.

The film may be, for instance be Cryovac™ film. Low to zero mortality rate is obtainable with the packaging of the present invention. 

1. A method of packaging live seafood comprising the steps of providing a sealable container, wherein said container comprises a plastic tray having an interior volume and an upper peripheral edge, placing said live seafood in said container, and replacing the atmospheric gas in said container with a gas mixture comprising only CO₂ and O₂, with an O₂ content of at least 50% by volume, and a CO₂ content of at least 20% by volume, and sealing said container with a layer of flexible film comprising a sheet of flexible sealable film sealed to the upper edge of said tray, said flexible film having an Oxygen Transmission Rate (OTR) of at least
 1500. 2. A method as claimed in claim 1, wherein the OTR of said film is from 1500 to
 15000. 3. A method as claimed in claim 2, wherein the OTR of said film is about
 10000. 4. A method as claimed in claim 2, wherein said live seafood is mussels.
 5. A method as claimed in claim 2, wherein said live seafood is lobster.
 6. A package for use with live seafood comprising a tray with a flat floor and side walls extending upwardly from the floor, the side walls being of a sufficient height to accommodate a predetermined number of live organisms, said side walls being contiguous with one another and said floor to define a leak proof open tray, and the upper edges of said side walls formed flat lip extending around the peripheral edge of said tray; and a layer of flexible sealable film sealed to the upper edge of said tray to enclose a modified atmosphere comprising at least 20% CO₂ and at least 50% O₂, said flexible film having an Oxygen Transmission Rate (OTR) of at least 1500 cm³O₂/m²/day bar.
 7. A package as claimed in claim 6, wherein the tray is substantially rectangular, and the corners of said rectangular tray are rounded.
 8. A package as claimed in claim 7, wherein said tray is molded from plastic.
 9. A package as claimed in claim 7, wherein said film, has an OTR in the range of 1500 to 15000 cm³ O₂/m²/day bar.
 10. A package as claimed in claim 7, wherein the OTR of said flexible film is about 10,000 cm³ O₂/m²/day bar to above 250,000 cm³ O₂/m²/day bar. 